instance
When an instance has both IPv4 and IPv6 ephemeral IPs, the ip_version query parameter must be specified to identify which IP to detach.
delete
Query Parameters
v4v6
The IP version of the ephemeral IP to detach.
Required when the instance has both IPv4 and IPv6 ephemeral IPs. If only one ephemeral IP is attached, this field may be omitted.
The IP address version.
Name or ID of the project